package simple.entity

class Book extends Publication {
    def attachBorrower(borrower) {
        this.borrower = borrower
    }

    def detachBorrower() {
        this.borrower=null
    }

    @Override
    String toString() {
        return 'Book:'+super.toString()+" => by:${author}"
    }
    //----------properties----------

    def  author
    def borrower =null
}